Electric vehicles—i.e. vehicles propelled by one or more electric motors—are powered by large, rechargeable batteries. Electric vehicles are limited by available battery technology, which limits the range per charge for most electric vehicles. For widespread deployment and use of electric vehicles to be feasible, there must be widely available recharging stations, such as in homes and public locations.
Electric Vehicle Supply Equipment (EVSE) includes chargers and charging stations for electric vehicles. The EVSEs regulate the amount of power that the electric vehicle draws from the charging station. The electric vehicle is connected to a cable from the EVSE using a special connector, such as an SAE J1772-compliant connector. The connector may include a number of pins corresponding to different connections between the electric vehicle and the EVSE, such as a 120 V AC line, a 240 V AC line, a ground line, a pilot wire, and other connections. When the electric vehicle is connected to the EVSE, the pilot wire is used to regulate the electricity available to, and/or drawn by, the electric vehicle. A Pulse Width Modulation (PWM) control signal is carried on the pilot wire between the EVSE and the electric vehicle. The duty cycle of the PWM signal indicates to the electric vehicle whether it should recharge by drawing power from the 120 V AC line, or the 240 V AC line, for example.
The EVSE is coupled to a power line network, such as an electrical distribution network for a home, and regulates the electricity drawn by the electric vehicle from the power line network. Power line communications are used on some power line networks to transmit data and communication signals. Because the electric vehicle is coupled to the power line network via the EVSE cable, power line communications may be routed between the electric vehicle and modems on the power line network.